1. Field of the Invention
The present invention relates, in general, to atomizers and, in particular, to a new and useful device for atomizing soil or other substances having a high solids content.
2. Description of the Related Art
Atomizers have long been used to disperse liquids or slurries into a spray of droplets. The energy required to break up and disperse the liquid or slurry into droplets comes from a variety of sources. With dual fluid atomizers, this energy comes from a high velocity gas that provides the shearing forces necessary to break the liquid or slurry into droplets. The gas used for atomizing the liquid is usually air or steam. The gas and liquid are either mixed internal to the atomizer and discharged through holes at high velocity, or the high velocity gas and liquid are mixed external to the atomizer.
The diameter of the passages that discharge the gas, liquid, or gas-liquid mixture are usually of a small diameter ranging anywhere from 0.05 to 0.3 inches so that high velocities can be obtained at the desired flow rates of gas and liquid.
Dual fluid slurry atomizers have been developed for atomizing liquid-solid mixtures. These slurries contain small solid particles that are suspended in the liquid. Caution must be used when atomizing slurries to insure that the largest solid particle of agglomerate of particules in the slurry can easily pass through the smallest diameter passage of the atomizer. Examples of slurry atomization are lime and flyash slurries used in dry sulfur removal devices in the electric utility industry, spray drying, and coal-water fuel used as a substitute for fuel oil in combustion processes.
In all of these applications, the mass fraction of solids in the slurries or the chemistry of the slurries are designed so that the slurries have flow properties similar to liquids. That is, the slurry viscosity is sufficiently low so that it can be transported through pipes using traditional or wear-resistant pumps. These slurries are usually limited to solid mass fractions on the order of 50%. By using specialized chemistry and control of the particle size distribution, solid mass fractions on the order of 70% can be attained.
Presently, there is no known atomizer which can accommodate high solid slurries with large particle diameters while at the same time provide efficient flow rates.